shithub: riscv

ref: dde3628d54073e0569bf565e6ec861e42cfa35f6
dir: /sys/man/2/runecomp/

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.TH RUNECOMP 2
.SH NAME
runecomp, runedecomp, fullrunenorm, runegbreak, runewbreak, utfcomp, utfdecomp, fullutfnorm, utfgbreak, utfwbreak \- multi-rune graphemes
.SH SYNOPSIS
.ta \w'\fLchar*xx'u
.B #include <u.h>
.br
.B #include <libc.h>
.PP
.B
int	runecomp(Rune *dst, Rune *src, int max)
.PP
.B
int	runedecomp(Rune *dst, Rune *src, int max)
.PP
.B
Rune*	fullrunenorm(Rune *s, int n)
.PP
.B
Rune*	runegbreak(Rune *s)
.PP
.B
Rune*	runewbreak(Rune *s)
.PP
.B
int	utfcomp(char *dst, char *src, int max)
.PP
.B
int	utfdecomp(char *dst, char *src, int max)
.PP
.B
char*	fullutfnorm(char *s, int n)
.PP
.B
char*	utfgbreak(char *s)
.PP
.B
char*	utfwbreak(char *s)
.SH DESCRIPTION
These routines help in handling
graphemes that may span multiple runes.
These routines are for use in font rendering
and advanced text search; most programs do not
need to perform normalization.
.PP
.IR Runecomp ,
.IR runedecomp ,
.IR utfcomp ,
and
.I utfdecomp
perform Unicode® normalization on
.IR src ,
storing the result in
.IR dst .
No more than
.I max
elements will be written, and the resulting string
will always be null terminated. The return value
is always the total number of elements required to
store the transformation. If this value is larger
than the supplied
.I max
the caller can assume the result has been truncated.
.I Runecomp
and
.I utfcomp
perform NFC normalization while
.I runedecomp
and
.I utfdecomp
perform NFD normalization.
.PP
.IR Fullrunenorm ,
and
.I fullutfnorm
determine if enough elements are present in
.I s
to perform normalization. If enough are present,
a pointer is returned to the first element that begins
the next context. Otherwise
.I s
is returned. No more then
.I n
elements will be read. In order to find the boundary, the
first element of the next context must be peeked.
.PP
.I Runegbreak
and
.I utfgbreak
search
.B s
for the next grapheme break opportunity.
If none is found before the end of the string,
.I s
is returned.
.PP
.I Runewbreak
and
.I utfwbreak
search
.B s
for the next word break opportunity.
If none is found before the end of the string,
.I s
is returned.
.SH SOURCE
.B /sys/src/libc/port/mkrunetype.c
.br
.B /sys/src/libc/port/runenorm.c
.br
.B /sys/src/libc/port/runebreak.c
.SH SEE ALSO
Unicode® Standard Annex #15
.br
Unicode® Standard Annex #29
.br
.IR rune (2),
.IR utf (6),
.IR tcs (1)
.SH HISTORY
This implementation was written for 9front (March, 2023).